import React, {Component} from 'react';

interface Istate {
    name:string
}

export default class App extends Component<any,Istate> {
    state = {
        name: 'hhl'
    }

    render() {
        return (
            <div>
                {this.state.name.substring(0,1).toUpperCase() + this.state.name.substring(1)}
                <button onClick={() => {
                    this.setState({
                        name: 'sqy'
                    })
                }}>click</button>
            </div>
        )
    }
}